Intermittent over exposure

[Markgibson3027]

1dx

When using my x2 teleconvertor and 300mm f2.8 mkii I occasionally get over exposure issues. I shoot in manual with auto iso 50% of the time it exposes perfectly. I then get loads of images totally over exposed. Tried all different metering types. Sometimes the over exposure is almost 2 stops. Sometimes by removing the lens and refitting helps. Any solutions please because this is now causing me many hours of grief and 100's of lost pictures.

[Waddizzle]

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@Markgibson3027 wrote:
It just seems strange that images minutes apart can't become greatly over exposed. I've shot my 100-400 on the same body for over 6000 shots with only the occaonal over exposure. Now using the 300 f2.8 and x2 teleconvertor I've shot with around 30% over exposed. I don't think it's the user I think it could be something technical. Although I am new to using a prime lens.

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Are you using any sort of filter on the lens?  I only use B+W Nano Clear filters on my “L” lenses.  Other filter types seem to affect the focusing ability, not the exposures though.

[Waddizzle]

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@Markgibson3027 wrote:
It just seems strange that images minutes apart can't become greatly over exposed. I've shot my 100-400 on the same body for over 6000 shots with only the occaonal over exposure. Now using the 300 f2.8 and x2 teleconvertor I've shot with around 30% over exposed. I don't think it's the user I think it could be something technical. Although I am new to using a prime lens.

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Using the teleconverter can slow everything down.  What happens to exposures when you do not use it?

I am guessing that you are using AI Servo focusing mode, and Continuous Shot shooting mode, with that setup.  How is your Image Priority set?  I have both 1st and 2nd Image Priority set for full tilt Focus Priority, which means that camera waits for a focus lock before it fires the shutter in Continuous Shot mode.  This may also have an collateral impact on metering, too.

[Markgibson3027]

Not using any filters.

[Markgibson3027]

I will tey to change this again. When I 1st had the issue i changed the 1st and 2nd shot priority thinking this could be the issue. And it still occurred. This weekend I will try with the 1.4 teleconvertor and see if this has any direct impact.

[Ray-uk]

1st & 2nd shot priority is related to autofocus and has nothing to do with exposure.

[Waddizzle]

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@Ray-uk wrote:

1st & 2nd shot priority is related to autofocus and has nothing to do with exposure.

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You are correct.  However, if the lens is OOF, then can not metering become somewhat impaired?  Changing metering mode from the factory default, Evaluative Metering, can also cause the occasional series of bad exposures.  I see little reason to use the other metering modes, not unless you are using a tripod, or have hands of steel.

I used to have the randoml occurring run of bad exposures far too often to my liking  I cannot point blame anything specific, but I top suspect is that I was unknowingly locking exposure.  Paying more attention to fingers seem to have cured it..

[ebiggs1]

The areas where this can happen is this, "I shoot in manual with auto iso 50% of the time it exposes perfectly."  So stop using auto ISO.  If you check the exif it will probably be very high. Out of reason high.

If that checks out a lens communication between the lens your tel-con and camera.  Remove the tel-con. Try it again.

If that checks out the mirror can get lazy and remain partly open. Also mirror bounce can cause this.  You will need to have Canon service it with a C&C.

Lastly user error.